astronomy

Oddmints

Venus and Mercury. It is unusual to see Mercury so clearly (bottom right), as it was approaching maximum elongation (when the Sun, Earth and Mercury form a right angle). Uranus would also be in frame, as it was approaching conjunction with Venus, except it is far too dim to show up in this exposure of course. Neptune, if it were bright enough to see, would have just set.

The long exposure has given a pretty effect to a passing plane (top left).

Snowy Finchley!

A St. Valenteen’s Day card that I made for someone, it turned out they did not want it. It says ‘Lettuce bee Valentines’!

Magpie Mosaic. This is my hommage (French for ripoff) of South African photographer Johann Mader’s Mopane Mosaic. I like that he lists among his equipment, ‘beanbag’. In my picture, can you spot the cheeky magpie? :D

Look! A plane!

Oh noes! The Moon is going out

Being as how I am always banging on about the Moon and how great it is and how it is my favourite heavenly body (except maybe hott actress Jaime Murray obviously), it is a bit puzzling that I did not know there is a lunar eclipse happening tonight!

I noticed as I was popping to Tescos for an intresting snack that there was a little dark bite out of the Moon. I thought perhaps it was just a bit of cloud or something, but on the way back I realised it is a completely clear night. Then when I saw on one of the astro communities on my friends page about the eclipse, I promptly rushed out with the camera! (stopping only to take essential eclipse viewing equipmint such as BEER ekcetera).



It is great really as it is like the Universe itself is cheering me up! I just popped out for another look and it is close to totality right now. The darkened Moon has an eerie reddish glow for the same reason that sunsets do: its light is being scattered by dust in the Earth’s atmosphere. Of course we are not scared of eclipses because we are fantastically lucky enough to live in the 0.002% of human history which encompasses actually visiting the Moon, and playing golf there. But it must have been terribly frightening in nanshunt times when for no discernible reason the sky goddess became engulfed by darkness in a matter of minutes, and they must have been super relieved when she came back again.

I think that calls for another BEER :D

I do not know why people make such a fuss

It is easy to deal with being miserable as basically playing with computers all day takes your mind off it, and the rest of the time I am drunk!

Do not try to play with computers when youare drunk though as you get mixed up wtih what keys you are typing ekcetera and then you have mistakenly deleted the Internet or such.

It is OK really as I went to the shop there earlier and the Moon and Stars were out so I spent a pleasant while in the road looking at them. It is great that we have the Moon as otherwise it would be less intresting, also it would be awful lonely for the Earth not having company.

It is fantastic at the moment as the Moon is really close to Saturn! If you look at it it is obvious what I mean. Also they are being followed across the sky by Leo, which is the bringer of Spring and although it is a lion, it is not the scary kind like you might think. It is more like Aslan. A cheerful lion that is concerned for your welfare.

Star party

You would not think you could see an awful lot of stars in London, and indeed it is a whole different story when you get out into the country at night and the great glittering wheel of the Galaxy above you takes your breath away. Still if you can just get a bit away from street lights (like in the car park at the back of the little flat) you can see some lovely stars such as eg Sirius - above right of the big tree - and Rigel - top right corner and it is Orion’s left foot. This link is a nice example of what can be done in dark skies (with a long exposure).

I got myself a new tripod while I was in Cornwall, and it is really good for night time photos and long exposures ekcetera. It is even better now my Dad fixed it so a tiny importint plastic bit does not drop out of the tripod when you open it up rendering it basically useless.

If you have ever done astro photography you will know one of the most difficult things is just getting the camera in focus to start with. The EOS350D is not the best for this as its viewfinder is awful small and dim. There is a magnifier ( the Canon Magnifier-S ) you can get that attaches on to it like a little jeweller’s loupe; I am going to try and get one of those. In the meantime all you can do really is take a lot of test shots and use the digital zoom to check the sharpness until you get it right. One thing which would make this very much easier is if you could preview the image on the LCD screen. Of course the mirror is in the way being an SLR, but there is a mirror lock-up function so it could be done. (Edit: The EOS20D does this.)

A starfield in Orion, with the Great Nebula centre. This is applying a bunch of computer techniques I have read about eg Going Deep with a DSLR and Neutralising the Sky Background and using the Dcam Noise 2 Gimp plugin. Here is the original image so you can see the difference. Basically good astro processing comes down to a judicious use of the Curves tool, a little Selective Gaussian Blur, and lots of experimintation. You also need to take a lot of frames to start with as some of them will mysteriously turn out shite.

This is the best shot I have got of the Orion Nebula so far thanks to my new tripod. I read a good tip on the web somewhere as well which is not to turn up the ISO setting on the camera as you would normally think to do for low light photography, because it is not a ‘sensitivity’ setting as it is with film. Instead it controls the gain that amplifies the signal from the CCD, so you are not capturing any more photons - just amplifying CCD noise along with the same number of photons. I will use a low ISO with a longer exposure next time.

Close-up of the nebula, enhanced as well as I can do and slightly blown up, but at this level optical artefacts start to dominate and obviously it does not really look like that in terms of nebulosity ekcetera. Still it is quite recognisable (see this gorgeous mosaic from Hubble for probably the most detailed picture of the nebula ever made). I am very pleased with the Dcam Noise plugin though as I expect even better results next time when I am using minimum ISO gain (hence minimum noise) on the CCD. There were 8 or 10 obvious hot pixels left which I removed by hand. I am also going to do some dark frame subtraction next time I go out; I did not have time this time because it was getting cloudy!

A nice picture of the Moon which could have been even better except some hazy cloud was rolling in and consequently it is lacking a little definition. Still the ray structure of Tycho is clearly visible ( left, below centre ). The small bright spot just left of top centre is the crater Aristarchus. I hope you like it as I think the Moon is beautiful and sometimes I just like to sit and look at it out the window. Not in a scary way though.

Stars

I could not sleep last night so I got up and sat by the window in the living room for a while, just enjoying the stars and watching the clouds roll by. Orion was so clear that I thought I would take a quick photo or two. I have done a post about Orion before, but hopefully you will not mind.

I have magnified a small section of the three ‘sword’ stars hanging below Orion’s belt, the middle one is actually the Great Nebula if you do not know. It is probably one of my favourite vast interstellar clouds of glowing dust and gas. You can see that it is quite fuzzy compared to the stars above and below it (even allowing for the stars being smeared out owing to cheap optics and my heartbeat).

There is a huge dark cloud in Orion where new stars are being born; the Nebula is the result of one of them illuminating a tiny section of the cloud which formed it, like a soldier lighting a cigarette in No Man’s Land. I do not know if you like to find out about the Universe and stars ekcetera but I do, as I am pretty intrested in local history.

This is with the EOS350D and 200mm Sigma zoom, hand-held out of my window at ISO1600 and at a 1 second exposure (steadied against the window sill!) I have cut out the red channel using the Channel Mixer tool in GIMP so as to reduce the skyglow and cloud. That is why it looks a bit green and sickly. Normally with star photos you can get good results with fairly savage compression using the Curves tool as a total bandpass filter, but I wanted to show you how fuzzy the nebula looks! You can see this quite easily with cheap binoculars in any case, or if you have amazingly powerful eyes that you borrowed from some eagle.

El Terror del Marte

It is hard to imagine what kind of cataclysm could cause Mars to appear as large in the sky as the full Moon, but it would probably mean the destruction of the Solar System as we know it and thus the end of all humankind.

That does not seem to stop the annoying e-mail circulating which says that Mars will be making its closest approach to Earth for 5,000 years (true, but this happened three years ago) and that Mars will look as large as the full Moon.

How could this possibly be true? Mars is about twice the size of the Moon, so a little elementary arithmetic reveals that if it looked the same size, it would be twice as far away; in other words, the Moon would be about half way between Earth and Mars. That’s wrong by a factor of about two hundred. This is the kind of order of magnitude error that you would be making if you thought I was 1200 feet tall, or that England and France are 4,000 miles apart. It’s not even vaguely plausible.

I think this is telling us that we have a worrying lack of basic astronomical literacy. Consider a circulated email which warned that the average temperature in England this summer would be 3,000 degrees Centigrade. This is wrong by approximately the same amount as the Mars meme, yet we wouldn’t give it a moment’s credence. It’s so obviously, hugely divergent from reality that we would assume immediately that it was a joke, or a typo.

It looks as if this is what happened with the Mars alert, as if you read the text carefully you can see that the confusion is caused by a rogue paragraph break:

The encounter will culminate on August 27th when Mars comes to within 34,649,589 miles of Earth and will be (next to the moon) the brightest object in the night sky. It will attain a magnitude of -2.9 and will appear 25.11 arc seconds wide. At a modest 75-power magnification

Mars will look as large as the full moon to the naked eye.

The important bit is easy to miss: at a modest 75-power magnification. In other words, through a fairly decent telescope, Mars will look a similar size to that of the full Moon seen with the naked eye.

But this is stupid! Through a telescope, anything could look as big as anything else! You could say that at a modest 1,000-power magnification, an ant will look as large as a human being to the naked eye. That’s what a telescope is for. It magnifies things.

The circulation of this rubbish has become an annual event and wastes an awful lot of people’s time and inbox space, and the reason I mention it is that I see it has now been translated into Spanish - omitting, of course, the crucial qualifier.

Desmienten rumores sobre acercamiento de Marte a la Tierra (El Universal)

Rumors denied about Mars’ approach to Earth

(quoting from the e-mail)

El encuentro terminará el 27 de agosto, cuando Marte este a 55.439.342 Km de la Tierra. Entonces, junto con la Luna será el objeto más brillante en el cielo nocturno.

The encounter will end on 27th August, when Mars will be 55,439,342km from Earth [true]. At that time it will be, together with the Moon, the brightest object in the night sky.

A simple vista Marte parecerá tan grande como la Luna llena y será fácil de ver.

To the naked eye Mars will appear as large as the full Moon and will be easy to see. [no kidding]

The Bay of Rainbows

I was watching an exciting movie about space (Event Horizon) but I kept noticing actual space out of the window behind the screen; the great shining pregnant Moon riding clouds in a dark sky. I think I would have been all right in the days before telly as I can sit and look at the Moon and stars for hours, as everyone who knows me can testify with some annoyance.

I do not know why I never thought of it before but the little binoculars that Steve the Sheep gave me for bird noticing also come in handy for Moon noticing! Looking at our nearest neighbour with the naked eye is a bit disappointing as you can see a vaguely familiar pattern of dark smudges, or a face, depending how many and what grade of drugs you’ve smoked. But a zoom lens or even the smallest binoculars teleport you into a breathtaking landscape of craters and dark seas, hard-edged and glowing in brilliant sunlight against the pure blackness of space.

It is even more amazing through a decent telescope: the image that swims into focus in front of you is so clear and sharp that it is like looking at really high-quality satellite photographs. You feel that if there were people down there you’d be able to make out their license plates and newspaper headlines. It brings it home to you with a gut immediacy that you are looking down on an alien world, and it’s real.

The photo (by Eric Roel) shows a detail of the Mare Imbrium, the Sea of Rains.

To find it, look for the three roughly similar sized-blobs at the top right of the Moon’s face (if you’re in the Northern Hemisphere, otherwise, the bottom left) and go left to the large dark area above the bright pinpoint crater Copernicus. This is the Mare Imbrium. Now look at the patch of lighter highlands to the north - the ‘shoreline’. There is an almost perfect semicircular notch out of it. This is Sinus Iridium: the Bay of Rainbows. What an amazing name!

You can’t help looking at the Moon differently when you know there’s a Bay of Rainbows up there.

Orion

Orion is probably the most obvious and striking constellation, and it is a great starting point for learning your way around the stars.

You can see that he is raising a club or a spear above his head, and holds a bow - Orion is the great hunter, centrepiece of the winter sky. He is perpetually locked in combat with Taurus, the Bull. Below his belt hangs what we politely refer to as his ‘sword’, though other cultures have identified it with a different item of gentleman’s equipment.

The sword hides a secret. Its middle star is not a star at all, but a vast glowing cloud of gas and dust, the Great Nebula in Orion. This cloud is about 30 light years across, big enough to encompass our Sun and its nearest twenty or thirty neighbours. Inside, new stars are forming with what seem to be the precursors of planets. The Nebula appears unremarkable in visible light, but if we could see in the infrared, it would be a great blazing splash across the sky, four times the size of the full Moon:

(Image from seds.org. This is on approximately the same scale as the picture above.)

Sirius

If you take a line through the stars of Orion’s belt and follow it down and to the left you will come to Sirius, the brightest star of all. Sirius is called the Dog Star because it is in the constellation of Canis Major, the larger of Orion’s two hunting dogs. Sirius is a southerly star, so for northern hemisphere observers it generally appears low on the horizon, like here:

Sirius over Mill Hill village

Procyon

If you look up from Sirius you will see another bright star at the left of Orion, sort of on its own. This is Procyon in Canis Minor, the lesser dog. We’re always hearing a lot about Sirius, but you don’t often see press releases about what Procyon’s up to. It must get a bit frustrating sometimes always being the Number Two. I like Procyon the best.

If you follow a line up from Sirius through Procyon and a bit to the left, hovering over Orion’s shoulder you will see Gemini, the Twins, which we covered in a previous lesson (pay attention at the back).

Aldebaran and the Pleiades

Now go back to Orion and extend the line between Orion and Sirius in the opposite direction. You will come to a bright red star, Aldebaran, the glowing eye of the Bull which always faces Orion. If you keep going you will see a fuzzy patch of middling bright stars, the Pleiades.

Aldebaran and the Pleiades

Happily, Mars wanted to be in this picture too, so it sidled in at the last minute.

Looking more closely at the Pleiades in this 100% crop we can see the Seven Sisters (Alcyone, Merope, Maia, Electra, Taygeta, Celaeno and Asterope) and their parents Atlas and Plione. Alcyone is the eldest sister so she is always in charge if Atlas and Plione go out, which sometimes leads to friction with little Asterope wanting to stay up late and watch TV.

In fact although you can see six or seven stars with the naked eye, there are about 3,000 stars in the Pleiades cluster. That might seem a lot until you realise there about four hundred billion stars in the Galaxy. The Galaxy is so vast that it beggars comprehension. It is about 100,000 light years across, which means absolutely nothing to us humans, but if the whole Solar System were shrunk to the size of a golf ball, the Galaxy would be about the size of North America.

For a minute the Galaxy almost seems impressively large, but it is just one of hundreds of billions of galaxies. There are probably as many galaxies in the Universe as there are stars in our Galaxy. If you start thinking about this type of thing it tends to make your head go a bit woozy and you have to have a sit down. The numbers involved are so much bigger than anything our brains evolved to cope with, we can’t even get a vague sense of the size of the Universe. Whenever you think about it there is a feeling of standing dizzily at the edge of some appalling abyss. Every time you look up into the night sky you are literally staring into infinity.

And we are journeying through that infinite cold, dark void, in a tiny blue spaceship. Unfortunately we are not carrying any spares in the boot so if anything goes wrong with the spaceship, we are pretty much screwed. It is enough to make you drive a bit more carefully.